The use of precast panels for modular construction of buildings is well known. Three different construction systems using solid precast panels are shown in U.S. Pat. Nos. 1,924,801; issued: Aug. 29, 1933; 2,078,144; issued: Apr. 20, 1937; and 3,685,241; issued: Aug. 22, 1972.
These aforementioned patents teach various methods for attaching corner panels to side panels. Amongst these methods are the hanging of the wall panels by means of eyelet fasteners and hooks (U.S. Pat. No. 2,078,144); and nut and bolt fasteners (U.S. Pat. No. 1,924,801).
Of the three methods, the most popular fastening system is the nut and bolt technique, which is commonly in use today with precast waffle panels.
Waffle panels have recently become popular because of their light weight, yet rigid construction provided by internal reinforcing ribs. These waffle panels find particular applicability in the construction of utility structures and multi story masonry buildings.
The corners for waffle constructed buildings are presently achieved by overlapping the ends of adjoining side wall panels. For some strange reason, no one has seen fit to cast a special corner panel for waffle structure.
While the overlapping of the side panels is adequate in providing a workable corner construction, certain problems exist with this technique:
1. When two standard eight inch (8") panels overlap a panel of even length, the resultant wall does not maintain the desired two foot (2') incremental dimension. Special, non-standard panels become necessary to maintain proper dimensioning, thus adding time, complexity and expense to what is ordinarily a simple procedure.
2. The overlap is void of a corner reinforcement (internal vertical) rib upon which furring strips for interior finishing can be hung.
3. The attachment bolt passes through the waffle recess of the overlapping panel, which creates a weak area of attachment.
4. The nut attaching to the bolt is only possible on the outside of the panel, thus creating an unsightly protuberance on an otherwise smooth wall. In addition, the through hole creates a potential spot for ground water leakage through foundation walls. For this reason, among others, precast waffle panels have not been widely used in foundation construction.
5. With the overlap technique, the space between adjoining panels, useful for providing for expansion and contraction therebetween, will vary and create a problem wherein shims are required for proper joint widths, thus producing uneven compression in the joint seal.
The present invention seeks to eleviate all of the above drawbacks by providing a precast waffle corner panel. The corner panel of this invention has reinforcing ribs that define the internal recess wherein a bolt and nut can provide fastening between a corner and side panel from the inside.